HABITS can affect the orofacial structures and can influence the facial growth, oral function, occlusal (bite) relationships, and facial aesthetics of a person. A multitude of factors influences the early growth and development of the facial region. In other words, a child may even grow not resembling his or her parents because of certain deleterious habits extant during the formation years.

The main functions of the oral cavity are respiration, swallowing, mastication and speech. Newborn infants are obligatory nasal breathers, but the lower jaw and tongue must be positioned away from the throat for the airway to be patent. If nasal breathing becomes obstructed, oral breathing must commence. Respiratory needs, therefore, can be a primary determinant of lower-jaw posture and tongue position in the later years. Respiratory and swallowing movements are activities, which have been noted in utero. In fact, it is not unusual to detect a foetus sucking its thumb even four months before being born. At birth, the infant exhibits two reflexes that are related to sucking. The root reflex, which lasts until the child is approximately seven months of age, is the movement of an infant’s head and tongue toward a stimulus touching the infant’s cheek.

The sucking reflex, active movements of the infant’s muscles surrounding the mouth, expresses milk from the nipple and lasts for approximately 12 months. To obtain milk from the mother’s breast, the infant does not need to suck but instead stimulate the smooth muscle in the breast to contract and express milk onto the tongue; this is called suckling. The milk is carried to the throat and gullet by the tongue. The infantile swallow does not occur the same way as in the case of the adult. It is characterised by the infant placing the tongue beneath the nipples, contracting the lower lip, and swallowing with the lips together and jaws apart. On the other hand, the adult swallow is characterised by a teeth-together swallow, with the tongue against the palate and lips relaxed. The transition from the infantile way of sucking to the adult way is gradual and disruption of its normal process can result in abnormal physical changes in the middle and lower sections of the face.

When a child who is more than three years old habitually sucks his/her fingers, it can give rise to 12 different harmful effects that eventually lead to a disfigurement of the entire dentition, upper and lower jaws, upper and lower lips, and palate. The aftermath, which depends on the habit’s frequency, intensity, and duration, is invariably an adulteration of the child’s beauty. The term adenoid facies has been used to describe the facial appearance of patients with a long face and anterior open bite. This comes from habitual mouth-breathing. More specifically, these patients demonstrate a downward and backward rotation of their lower jaws during growth, excess eruption of posterior teeth, upper jaw constriction, anterior open bite and increased anterior (especially lower) facial length.

The instances whereby harmful habits during a person’s tender years can modify their facial appearances are too numerous to mention here. However, the advice given is that professional intervention should be sought whenever a young child is observed to be practising abnormal habits with the mouth.